Calcarina capricornia, Mamo, Briony L., 2016

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 102-103

Calcarina capricornia n. sp. ( Fig. 24 :5–14)

1965 Calcarina hispida Brady ; Jell et al., 277, pl. 44, fig. 3.

2002 Calcarina spengleri Gmelin ; Lobegeier, p. 212, pl. 1, figs 1–8; pl. 2, figs 1–7.

Diagnosis. This species is determind by its large size, thick, coarsely perforate test wall featuring pustolose ornamentation and multiple spines that are canaliculate throughout.

Description. Test free, unequally biconvex and trochospiral. Large in size (1.3–1.6 mm diameter without spines), with thick, coarsely perforate test walls ( Fig. 24 :10) with calcite bosses on both the umbilical and spiral sides of the test, though in greater abundance on the spiral side. Five to seventeen thick spines with spikes extending from the test periphery that are canaliculate throughout ( Fig. 24 :5, 12, 14). Chambers slightly inflated with depressed sutures clearly visible on umbilical side ( Fig. 24 :8, 9).

Remarks. This species is characterised by its thick, coarsely perforate test wall, its large size, visibly depressed sutures and its large number of spines that are canaliculate throughout.

Calcarina capricornia bears similarity to Calcarina hispida Brady 1876 but C. hispida has a non-perforate test that is smaller in size and its spines are non-canaliculate in the centre ( Renema & Hohenegger 2005). Additionally, C. capiricornia does not possess the same mass of hispid spines across the test that cover the test so thickly that they obscure the sutures except for the final few chambers. Calcarina exuberans Debenay 2013 (previously Calcarina hispida var. pulchella Chapman 1900 ) bears similarity to C. capricornia , particularly with the large number of thick spines, however the test wall is much thinner, the spines are more numerous and more varied in nature and the test is smaller—the same size as C. hispida . Calcarina capricornia additionally lacks the distinct “exuberant” outgrowths on the extremities of the spines that make C. exuberans so distinctive. Calcarina gaudichaudii d’Orbigny 1840 is similar to this species in that they both possess distinctly thick, perforated test walls yet C. gaudichaudii has a much smoother test with smaller calicitic bosses, a pinched periphery, and bears fewer spines which are more regular, without spikes and have a blunted tip.

Intraspecific variability includes the number of spines and the abundance and distribution of the calcitic bosses. Some specimens have calcitic bosses isolated to the central area of the test and others have them covering most of the test, including the spaces between spines.

This species has been previously recorded from the GBR on both Heron Island ( Jell et al. 1965) and Green Island ( Lobegeier 2002). Jell et al. (1965) reported this species where it commonly constituted 50% or more of sedimentary grains, but was not present in dredged samples from deeper waters and Lobegeier’s (2002) investigation found them to be a robust species habituating areas of high UV-radiation levels and high energy reef flat environments within strands of filamentous turf algae including Laurencia sp. and Chlorodesmis fastigiata .

Derivation of name. This species is named after the region from the southern GBR where it was collectedthe Capricorn Group.

Material. Holotype—QM#G465953 ( Fig. 24 :5); Paratypes QM#G465800 ( Fig. 24 :6, 7), QM#G465799 ( Fig. 24 :8, 9), QM#G465783 ( Fig. 24 :10), QM#G466041 ( Fig. 24 :11, 12) and QM#G466047 ( Fig. 24 :13, 14), all specimens were retrieved at a depth of 3 m or less from Heron Reef flat, Capricorn Group, Great Barrier Reef, Australia, Holocene.

Distribution within study area. Calcarina capricornia was collected from all sampled reefs and often accounted for 50–75% of all specimens collected from each site. In fact, C. capricornia was the most abundant species from the CG, accounting for 38.6% of the total number of foram specimens collected. This species occurs in shallow, high energy, tidally influenced waters across reef flat areas similar to other Calcarina species ( Hohenegger et al. 1999; Lobegeier 2002; Yordanova & Hohenegger 2002; Renema & Hohenegger 2005). Sites of low abundance include site 10 along ST transect and site 15, along transect 2 across Heron Reef flat where the edge of the reef flat becomes pure reef platform to rubble zone and there are low levels of sedimentation and algae growth. Additionally, the three deepest sites within Heron Lagoon also have the lowest abundance. The same pattern occurs in Wistari and One Tree Lagoons. Of note is that where the abundance of C. capricornia decreases, the abundance of B. sphaerulata often increases. The most extreme example of this case occurs at site 15 along Transect 2 of Heron Reef and site 28, Sykes Reef and is likely due to a shift in dominant algal type in different regions of the reef flat.

Figures

FIGURE 24. (Unless otherwise specified all scale bars = 100 µm). 1 – 4. Baculogypsina sphaerulata (Parker & Jones, 1860). 1 – 2. QM # G 465795 from T 2 – 3 lateral (1) and peripheral (2) views. Scale bar = 200 µm. 3. QM # G 465798 from T 2 – 3 lateral view. Scale bar = 500 µm. 4. QM # G 466108 from ST / HW 6 lateral view. Scale bar = 500 µm. 5 – 14. Calcarina capricornia n. sp.. 5. QM # G 466107 from ST / HW 4, spiral view. Scale bar = 200 µm. 6 – 7. QM # G 465799 from T 2 – 3 spiral (6) and umbilical (7) views. Scale bar = 200 µm. 8 – 9. QM # G 465800 from T 2 – 3 umbilical (8) and peripheral (9) views. Scale bar for 8 = 500 µm. Scale bar for 9 = 200 µm. 10. QM # G 465783 from ST / HW 10, spiral view. Scale bar = 200 µm. 11 – 12. QM # G 466041 from T 2 – 7, spiral (11) and peripheral (12) views. Scale bar for 11 = 500 µm. Scale bar for 12 = 200 µm. 13 – 14. QM # G 466047 from T 1 – 6, umbilical (13) and peripheral (14) views. Scale bar = 500 µm. 15 – 18. Calcarina mayori Cushman 1924. 15 – 16. QM # G 466048 from T 1 – 6, spiral (15) and periperhal (16) views. Scale bar = 200 µm. 17. QM # G 466050 from T 1 – 6, spiral view. Scale bar = 200 µm. 18. QM # G 466049 from T 1 – 6, umbilical view. Scale bar = 200 µm. 19 – 20. Cribroelphidium cf. C. excavatum (Terquem, 1875), QM # G 465785 from ST / HW 2. 19. Lateral view. 20. Peripheral view.